It is known to store certain drugs injectable by parental administration in liquid form in a container made from glass named “cartridge” having a diameter of 7 mm and sealed by a sealing washer. The drugs thus stored are ready to be used in syringes, for example, for dental care, or in injector pens.
Once filled with a drug, a cartridge is normally sealed by a sealing washer covered by a capsule made from aluminium. Said principle of sealing is widely used because it guarantees a good stability of the active principle of the drug, as well as the integrity of the drug to be conserved. With the current systems, the sealing washer is pre-installed inside the capsule made from aluminium, then same is crimped on the neck of the cartridge by means of a knurling tool. Such a method of crimping capsules made from aluminium is likely to generate debris from aluminium, glass or paint applied on the capsule made from aluminium, which makes said method incompatible with a use in a cleanroom of class ISO 5 according to the standard ISO 146 44. Moreover, there remains a risk of rotation of the sealing washer in relation to the cartridge, to the extent that the sealing washer does not fulfil the function thereof of isolation of the interior volume of the cartridge in relation to the exterior, hence a risk of deterioration of the active principle of the drug. Finally, the particles of aluminium, glass or paint released during the crimping are likely to pollute the upper surface of the sealing washer which is accessible via the capsule. During the perforation of the sealing washer for sampling the contents of the cartridge, said particles deposited on the surface of the sealing washer risk contaminating the product contained in the cartridge and, consequently, the patient. This is all the more significant as certain drugs packaged in cartridges are used for long-term treatments by means of injector pens, for example, insulin injector pens.
It is known from WO-A-94/04424 to use a cap made from multi-piece plastic material that is intended to be immobilised around the stopper of the sealing device. Said relatively complex structure is both expensive to manufacture and bulky, such that same is not adapted to the sealing of a container of small cross-sectional dimensions, such as a cartridge. Moreover, if the dimensions of the device known from WO-A-94/04424 were reduced in view of the use thereof on a container of small cross-sectional dimensions, such as a cartridge, the compressive force necessary for securing the stopper on the neck of the container would result in a radial expansion of said stopper likely to tear the cap.